arch/arm/kvm/handle_exit.c

   1 /*
   2  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
   3  * Author: Christoffer Dall <c.dall@virtualopensystems.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  */
  18
  19 #include <linux/kvm.h>
  20 #include <linux/kvm_host.h>
  21 #include <asm/kvm_emulate.h>
  22 #include <asm/kvm_coproc.h>
  23 #include <asm/kvm_mmu.h>
  24 #include <asm/kvm_psci.h>
  25 #include <trace/events/kvm.h>
  26
  27 #include "trace.h"
  28
  29 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
  30
  31 static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  32 {
  33         /* SVC called from Hyp mode should never get here */
  34         kvm_debug("SVC called from Hyp mode shouldn't go here\n");
  35         BUG();
  36         return -EINVAL; /* Squash warning */
  37 }
  38
  39 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  40 {
  41         int ret;
  42
  43         trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
  44                       kvm_vcpu_hvc_get_imm(vcpu));
  45
  46         ret = kvm_psci_call(vcpu);
  47         if (ret < 0) {
  48                 *vcpu_reg(vcpu, 0) = ~0UL;
  49                 return 1;
  50         }
  51
  52         return ret;
  53 }
  54
  55 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  56 {
  57         /*
  58          * "If an SMC instruction executed at Non-secure EL1 is
  59          * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
  60          * Trap exception, not a Secure Monitor Call exception [...]"
  61          *
  62          * We need to advance the PC after the trap, as it would
  63          * otherwise return to the same address...
  64          */
  65         *vcpu_reg(vcpu, 0) = ~0UL;
  66         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
  67         return 1;
  68 }
  69
  70 static int handle_pabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  71 {
  72         /* The hypervisor should never cause aborts */
  73         kvm_err("Prefetch Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
  74                 kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
  75         return -EFAULT;
  76 }
  77
  78 static int handle_dabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  79 {
  80         /* This is either an error in the ws. code or an external abort */
  81         kvm_err("Data Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
  82                 kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
  83         return -EFAULT;
  84 }
  85
  86 /**
  87  * kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
  88  * @vcpu:       the vcpu pointer
  89  * @run:        the kvm_run structure pointer
  90  *
  91  * WFE: Yield the CPU and come back to this vcpu when the scheduler
  92  * decides to.
  93  * WFI: Simply call kvm_vcpu_block(), which will halt execution of
  94  * world-switches and schedule other host processes until there is an
  95  * incoming IRQ or FIQ to the VM.
  96  */
  97 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
  98 {
  99         trace_kvm_wfi(*vcpu_pc(vcpu));
 100         if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE)
 101                 kvm_vcpu_on_spin(vcpu);
 102         else
 103                 kvm_vcpu_block(vcpu);
 104
 105         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 106
 107         return 1;
 108 }
 109
 110 static exit_handle_fn arm_exit_handlers[] = {
 111         [HSR_EC_WFI]            = kvm_handle_wfx,
 112         [HSR_EC_CP15_32]        = kvm_handle_cp15_32,
 113         [HSR_EC_CP15_64]        = kvm_handle_cp15_64,
 114         [HSR_EC_CP14_MR]        = kvm_handle_cp14_access,
 115         [HSR_EC_CP14_LS]        = kvm_handle_cp14_load_store,
 116         [HSR_EC_CP14_64]        = kvm_handle_cp14_access,
 117         [HSR_EC_CP_0_13]        = kvm_handle_cp_0_13_access,
 118         [HSR_EC_CP10_ID]        = kvm_handle_cp10_id,
 119         [HSR_EC_SVC_HYP]        = handle_svc_hyp,
 120         [HSR_EC_HVC]            = handle_hvc,
 121         [HSR_EC_SMC]            = handle_smc,
 122         [HSR_EC_IABT]           = kvm_handle_guest_abort,
 123         [HSR_EC_IABT_HYP]       = handle_pabt_hyp,
 124         [HSR_EC_DABT]           = kvm_handle_guest_abort,
 125         [HSR_EC_DABT_HYP]       = handle_dabt_hyp,
 126 };
 127
 128 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
 129 {
 130         u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
 131
 132         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
 133             !arm_exit_handlers[hsr_ec]) {
 134                 kvm_err("Unknown exception class: hsr: %#08x\n",
 135                         (unsigned int)kvm_vcpu_get_hsr(vcpu));
 136                 BUG();
 137         }
 138
 139         return arm_exit_handlers[hsr_ec];
 140 }
 141
 142 /*
 143  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
 144  * proper exit to userspace.
 145  */
 146 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 147                        int exception_index)
 148 {
 149         exit_handle_fn exit_handler;
 150
 151         switch (exception_index) {
 152         case ARM_EXCEPTION_IRQ:
 153                 return 1;
 154         case ARM_EXCEPTION_UNDEFINED:
 155                 kvm_err("Undefined exception in Hyp mode at: %#08lx\n",
 156                         kvm_vcpu_get_hyp_pc(vcpu));
 157                 BUG();
 158                 panic("KVM: Hypervisor undefined exception!\n");
 159         case ARM_EXCEPTION_DATA_ABORT:
 160         case ARM_EXCEPTION_PREF_ABORT:
 161         case ARM_EXCEPTION_HVC:
 162                 /*
 163                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 164                  * that fail their condition code check"
 165                  */
 166                 if (!kvm_condition_valid(vcpu)) {
 167                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 168                         return 1;
 169                 }
 170
 171                 exit_handler = kvm_get_exit_handler(vcpu);
 172
 173                 return exit_handler(vcpu, run);
 174         default:
 175                 kvm_pr_unimpl("Unsupported exception type: %d",
 176                               exception_index);
 177                 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 178                 return 0;
 179         }
 180 }